1. Field of the Invention
The present invention relates to a perpendicular magnetic write head provided with an induction type magnetic transducer element for write, method of manufacturing the same, and a magnetic write system which carries the perpendicular magnetic write head.
2. Description of the Related Art
In recent years, improvement is required in performance of a thin film magnetic head, which is mounted on magnetic write systems such as a hard disk drive, associated with improvement in the surface writing density of a magnetic write medium such as a hard disk (hereinafter just called “write medium”).
As examples of writing system of such thin film magnetic head, the longitudinal write system which sets a direction of signal magnetic field to an in-plane direction (longitudinal direction) of the write medium, and the perpendicular write system which sets up a direction of the signal magnetic field to a direction orthogonal to the plane of the write medium are known. Although the longitudinal write system is widely used nowadays, it is assumed that the perpendicular write system is more promising than the longitudinal write system in the future in consideration of the market trend, which is affected by improvement of the surface writing density of the write medium. It is because the perpendicular write system has advantages that high linear writing density is obtained and that an already-written write medium is hardly subject to heat fluctuation.
The thin film magnetic head of the perpendicular write system (hereinafter just called “perpendicular magnetic write head”) is provided with a thin film coil which generates magnetic flux and a main magnetic pole layer which leads the magnetic flux generated in the thin film coil to the write medium.
As an example of such perpendicular magnetic write head, those in which the main magnetic pole layer extends in a direction orthogonal to an air bearing surface are known and such a head structure is generally called “single pole head.” As for such single pole head, those in which an auxiliary magnetic pole layer for magnetic flux supply is put together with the main magnetic pole layer have been developed in order to increase intensity of the write magnetic field (perpendicular magnetic field) (reference to Unexamined Japanese Patent Publication No. H02-066710 and Japanese Patent Publication No. 2002-197615, for example). However, such single pole head is said to have a limitation in improving the writing density of the write medium.
As for a latest perpendicular magnetic write head, in view of the above, those provided with a write shield layer for taking in a spread component of magnetic flux emitted from the main magnetic pole layer are becoming mainstream so that the writing density can be more improved. This kind of head structure is generally called “shield type head.” As for such shield type head, those in which the write shield layer is disposed on a trailing side of the main magnetic pole layer have been developed (for example, refer to Japanese Patent Publication No. 2001-250204 and European patent Publication No. 0360978.
Especially about the shield type head, in order to suppress unintended erasure of information written on the write medium at the time of writing, those in which the auxiliary magnetic pole layer is disposed on the trailing side of the main magnetic pole layer are also developed (for example, refer to Japanese Patent Publication No. 2006-155866).
By the way, demand for writing performance of the perpendicular magnetic write head is still more increasing day by day. Based on such circumstances, it has been examined recently, as an improvement measure, to optimize a magnetic domain structure of main component elements that are engaged in writing operation.
Specifically, a magnetic film, which is made of a magnetic layer containing a magnetic metal and a transition metal and an intermediate layer containing a magnetic metal and a transition metal similarly, with its composition optimized in order to obtain high frequency characteristics, strong uniaxial anisotropy, and high saturation magnetic flux density, is known (for example, refer to Japanese Patent Publication No. 2000-150233). As well, a magnetic material, which includes nickel (Ni), steel (Fe) and molybdenum (Mo), with its composition and magnetostriction constant optimized in order to acquire high frequency characteristics and a good magnetic domain structure, is known (for example, refer to Japanese Patent Publication No. 2000-235911).
Besides, other well-known examples include: a thin film magnetic head, which is provided with an upper magnetic pole whose plus and minus of the magnetostriction constant are reversed between an upper area and an lower area thereof in order to acquire uniaxial anisotropy in a desired direction (for example, refer to a Japanese Patent Publication No. H07-307009 and a Japanese Patent Publication No. 1986-192011); a thin film magnetic head, which is provided with a yoke containing two sets of magnetic layers respectively having a mutually different magnetostriction constant and disposed so as to be partially overlapped each other in order to suppress generating of noises caused by stress induced anisotropy effect (for example, refer to Japanese Patent Publication No. H07-014120); and a thin film magnetic head provided with a pole chip having a zero or negative magnetostriction constant and a head core rear having a zero or positive magnetostriction constant in order to suppress distortion of a read waveform (for example, refer to Japanese Patent Publication No. H02-252111).
In addition, another known example is a thin film magnetic head provided with a magnetic domain control soft magnetic layer for making a 180 degree magnetic wall in a core width direction appear in a magnetic domain structure of a yoke of a magnetic layer between a coil cover which covers a coil layer and the yoke in order to obtain a good magnetic domain structure, high frequency response characteristics, and a high transfer rate (refer to Japanese Patent Application No. 2000-331310).
It is to be noted that, in the recent manufacturing field of thin film magnetic heads, the ALD method is used as the formation method which is extremely excellent in thickness control characteristics (for example, refer to an “ALD atomic layer deposition apparatus”, by Techscience Ltd., <URL:http://techsc.co.jp/products/mems/ALD.htm>). The ALD method is the step of forming an oxide film, a nitride film, or a metal film very thinly and precisely under high temperature conditions of 150 degrees C. or more, and is widely used in a manufacturing field in which physical characteristics such as dielectric strength voltage are severely required. In the manufacture field of the thin film magnetic head, the ALD method is used in the formation process of a read gap (for example, refer to the specification of U.S. Pat. No. 6,759,081).